In orthopedic surgery, drill bits have a tendency to skip or slide along the surface of a bone instead of boring into the bone as desired. This skipping or sliding is known as skiving. Skiving can alter the intended trajectory or position of a hole that is drilled into the bone. A drill guide can be used in some situations to help control the radial location and axial alignment of a drill bit. However, drill guides are typically limited to a single location and orientation to a desired datum.
During certain orthopedic surgery procedures a channel is cut into a bone. For example, during a spinal disc replacement procedure a channel can be cut into a vertebra of a spinal column. The channel is configured to receive an anchoring structure of an implant, such as a keel, to secure the implant within the spinal column. In softer bone, for example cervical vertebral bodies, a side-cutting drill can be used in a sweeping fashion to remove a channel of bone. In harder sclerotic bone, as is often found in the lumbar of the spine, the use or effectiveness of a side-cutting drill bit may be limited. Where a side-cutting drill bit cannot be used, a series of partially overlapping, in-line drill holes may be used to approximate the channel cut. The potential for drill skiving is magnified during a procedure that involves the drilling of sequential holes that are either overlapping or located close together, because the drill bit has a tendency to skive into previously drilled holes.
Traditional drill guides can be used to help control the location and alignment of a drill bit during a single hole drilling operation; however, they do not allow sufficient control of the location and orientation of several sequential drill holes that are either overlapping or located close together.